Carton clamp for lift trucks



Dec. 24, 1963 F. J. AVERY CARTON CLAMP FOR LIFT TRUCKS Filed Jan. 9, 1961 5 Sheets-Sheet l ATTORNEYS.

Dec. 24, 1963 F. J. AVERY CARTON CLAMP FCR LIFT TRUCKS s sheets-sheet 2 Filed Jan. 9, 1961 VEN TOR.' 4U/Mgg@ AToR/vfys.

Dec. 24, 1963 F. J. AVERY CARTON CLAMP FCR LIFT TRUCKS 5 Sheets-Sheet 3 Filed Jan. 9, 1961 m, 3 f im 1li N MLN m, qi- W n :e .M I E: B C i MH .Dillon llllnrl M United States Patent Otllice 3,115,262 Patented Dec. 24, 1963 3,115,262 CARTON CLAMP FOR LIFT TRUCKS Fred J. Avery, Chicago, Ill., assigner to Materials Transportation Co., Chicago, Ill., a corporation of Illinois Filed Jan. 9, 1951, Ser. No. 81,538 8 Claims. (Cl. 214-654) This invention relates to carton clamps for lift trucks and more particularly to a clamp construction capable of picking up one or more cartons from a series of closely stacked cartons in a warehouse, or the like.

In handling and storing relatively large appliancesk such as stoves, washing machines, dishwashers, andthe like, which are commonly individually packed in heavy paper board cartons, it is desirable and has been the common practice to grip the cartons individually or in multiples by clamps on a lift truck without the use of pallets. The usual practice is to provide clamp jaws engaging the sides of the cartons to pick them up and transport them.

This means that in storage spaces must be left between adjacent stacks of cartons intovwhich the clamp jaws can move. Normally such spaces areon the order of four inches to live inches so that the storage space required for a given number of cartons is substantially increased over that which would be required if the cartons were stacked in contact with each other. When cartons are stacked in contact with each other, it has been necessary' to take the cartons down singly by a crane and then to grip them by the clamp on the lift truck.

It is one of the objectsr of the present invention to provide a carton clamp which is capable of engaging one or more cartons from a closely stacked group without requiring any separate handling of the cartons.

Another object is to provide a carton clamp in which the carton is initially lifted by one or more vacuum cups engageable with the side face of the carton, providing clearance to enable clamp jaws to engage the top and bottom surfaces of the carton.

According to a feature of the invention, the vacuum cups are connected through lost motion connections to the upper clamp jaw so that the carton may be raised by raising the upper clamp jaw and the upper clamp jaw can move down into engagement with the carton without requiring release of the vacuum cup therefrom.

The above and other objects and features of the invention will be more readily apparent from the following description when read in connection with the accompanying drawings, in which:

FIGURE l is a partial side elevatiton of a conventional lift truck equipped with a clamp embodying the invention illustrating initial engagement with a carton to be picked up;

FIGURES 2, 3, and 4 are views similar to FIGURE l illustrating different progressive positions in the picking up of a carton with the clamp;

FIGURE 5 is an enlarged top plan view of the clamp structure;

FIGURE 6 is a partial front elevation of the clamp;

FlGURE 7 is a partial side elevation of the clamp;

FIGURE 8 is a view similar to FIGURE 7 of an alternative construction; and

FIGURE 9 is a partial front elevation of the clamp of FIGURE 8.

Referring first to FIGURES 1 to 4, the clamp is applied to a conventional industrial lift truck, partially indicated at 10, which carries a vertical mast 11 having a mounting plate 12 thereon to which different types of attachments may be mounted. The mounting plate 12 is movable vertically of the mast in the usual way so that the loads picked up by the truck may be picked up or deposited at different vertical levels. The mechanism by which this is accomplished forms no part of the invention and will not be described in detail herein.

The clamp of the invention comprises a vertically elongated frame, indicated generally at 13, which is supported on the mounting plate through mounting hooks partially indicated at 13' in FIGURE l in the usual manner. The frame, as best seen in FIGURES 5 and 6 may comprise vertical side uprights 14 which may be in the form of I beams, as seen in FIGURE 5, connected at their upper ends by a cross member 15. At the lower ends of the beams they lare connected by a clamp jaw 16 in the form of a relatively flat plate extending between the beams and projecting forward therefrom to underlie the bottom edge portionof a carton to be picked up. The plate 16 is preferably made as thin as is feasible in accordance with the loads to be handled so that where possible it can be slipped beneath a carton, or the like, to pick it up.

At its upper end the frame 13 supports a head 17 which is slidably vertically on the frame and which carries an outwardly projecting upper clamp jaw 18 adapted to engage and overlie the top of a carton. The head'17 may be moved vertically on the frame by a iluid motor 19 in the form of a hydraulic cylinder secured at its upper end to the cross member 15 of the frame and with its piston rod connected to a cross member 21 of the carriage 17. When fluid pressure is applied to the upper end of the cylinder 19 it will move the carriage downward to move the upper clamp jaw 18 downward into gripping engagement with the top of a carton to hold the carton between the upper and lower clamp jaws.

For initially engaging a carton in a closely stacked group there is provided, according to the present invention, one or more vacuum cups which will engage the front or exposed side of the carton to lift it suiiciently so that the lower clamp jaw 16 can move in beneath it. For mounting the vacuum cups, as shown, the frame includes at its opposite sides forwardly extending rails 22 on which carriages 23 are movable. As shown, the carriages 23 carry rollers 24 which roll on the upper and lower surfaces of the rails so that the carriages can move forward and backward without tilting. Each carriage carries a downwardly extending arm 25 which is rigidly secured at its upper end to the carriage to lie parallel to the frame at all times. A vacuum cup, indicated generally at 26, carries a tubular sleeve 2'7 which is slidable over each of the arms 25 for vertical movement of the vacuum cups relative to the upper clamp 18. Stop pins ZS in the arm 25 limit downward movement of each of the vacuum cups while leaving them free to move upwardly along the arms 25. The vacuinn cups are connected to a source of vacuum, such as a vacuum pump, on the lift truck through flexible hoses 29, as shown in FIGURES l to 4. It will be understood that the truck is equipped with suitable control valves accessible to the operator for opening or closing the vacuum hoses 29, as desired. l

For moving the carriages 23 forward or backward o the rails 22, a linkage is provided, as best seen in FIG- URE 5, comprising two levers 31 pivoted in the central part of the carriage with their free ends connected through links 32 to the carraiges 23 respectively. Springs 33 are connected to the levers 31 tending to urge them outwardly toward the position shown in FIGURES 1 and 5 in which the vacuum cups 26 are spaced outward from the frame to engage a carton. if desired, tluid motors 3d may also be connected to the arms to move them inwardly toward the frame in line with the frame uprights where they will not interfere with use of the clamp in a conventional manner. For many types of operations cylinders 312- are unnecessary and may be omitted.

For picking up a carton either from the floor or from a closely stacked group of cartons, the truck may be driven toward the carton at the proper level until the vacuum cups 26 are brought into engagement with the exposed side of the carton, as illustrated in FIGURE l. It will be noted that at this time the carriage 17 is lowered slight# ly below the top of the frame 13. When the vacuum cups have been brought into engagement with the side of the carton, the operator may open the vacuum valve so that the cups will be subject to a vacuum. It has been found that with a reasonable size of vacuum pump and with conventional types of cartons in which the surfaces are not extremely porous, a vacuum of about fifteen inches of mercury can be easily obtained. The vacuum cups may be made relatively large so that each cup when subjected to a fifteen inch vacuum is capable of lifting several hundreds of pounds. In actual operation with a unit according to the invention having vacuum cups of ten inches diameter and with two cups engaging a carton, it was found easily possible to lift cartons weighing as much as five hundred pounds.

With vacuum applied to the cups and the parts in the position shown in FIGURE l, the cylinder 19 is energized to elevate the carriage 17 and the upper clamp. The vacuum cups will be raised with the carriage at this time, thereby lifting the carton so that its lower edge is above the level of the bottom clamp jaw 16. Where the carton is being raised from a tightly packed group the truck may simply be moved forward at this time so that the bottom clamp jaw will move beneath the bottom of the carton and the top clamp jaw will be moved to a position above and in registration with the top of the carton. Where the carton is not backed up and can be pushed from the stack, the cylinders 34 may be used either to pull the carton toward the frame to a position between the jaws or could be employed in conjunction with movement of the truck toward the carton to accomplish the same purpose. In either case, the carton will be drawn against the frame with the parts in the position shown in FIGURE 3. To complete the clamping, the cylinder 19 is energized in the opposite direction to move the carriage and the upper jaw downward until the upper jaw engages the top of the carton. At this time, the arm 2S will slide freely relative to the vacuum cup 26 so that the carton can continue to be held by the vacuum cup until the jaws are in full clamping engagement therewith. At this time, the vacuum may be released and the carton may be transported to any desired point of storage or use.

FIGURES 8 and 9 illustrate an alternative arrangement for mounting the vacuum cup, all other parts being identical to corresponding parts in FIGURES l to 7 and being indicated by the same reference numerals. In the construction of FIGURES 8 and 9, the rails 22 and carriages 23 are replaced by a rocking shaft 37 on the head or carriage 17 extending transversely of the frame. The rocking shaft carries at its ends and adjacent to the sides of the frames open sleeve sockets 38 through which cup supporting arms 39 are slidable. Each of the arms 39 carries a stop pin 41 engageable with the top of the sleeve 38 to limit downward movement of the arm while leaving the arm free to slide upward through the socket. Each arm 39 carries one or more vacuum cups 42 similar to the vacuum cups 26. In this case, there are four vacuum cups, two at each side, for simultaneously handling two relatively large heavy cartons or four smaller and lighter cartons. It will be understood, of course, that any desired number of vacuum cups in any desired arrangement could be utilized to handle single or multiple cartons. As shown, the lower end of each arm 39 is connected through a horizontal pivot 43 with a support i4 on which the vacuum cups 42 are mounted.

In order to turn the rock shaft 37, an arm 45 is secured thereto and extends therefrom over the central part of the frame 13. A cylinder 46 secured to the head or carriage 17 has its piston rod connected to the free end of the arm 45 so that when the cylinder is expanded the arm will be swung to a vertical position,v 21S Shown in full lines in FIG- URE 8, and when the cylinder in is contracted the arm will be swung outward, as shown in dotted lines in FIG- URE 8, to move the vacuum cups forwardly into position to engage a carton or cartons.

rIhis construction functions and is used in the same manner as the construction shown in FIGURES l through 7. With the vacuum cups swung forwardly they may be rought into engagement with a carton and will lift the carton when the head or carriage 17 is raised by the cylinders 19. The arms 39 may then be swung back to their vertical position while the carton moves toward the frame and between the upper and lower clamp jaws thereon. When the head or carriage 17 is moved downward to bring the upper clamp jaw 1 into engagement with the top of the carton, the arms 39 will slide through the sleeves 3% so that the carton will continue to be held by the vacuum cups until the clamp jaws are in full clamping engagement therewith.

While two embodiments of the invention have been shown and described herein, it will be understood that they are illustrative only and not to be taken as a definition of the scope of the invention, reference being had for this purpose to the appended claims.

What is claimed is:

1. A carton clamp for use with a lift truck comprising an upright frame for mounting on a lift truck, a lower jaw secured rigidly to the lower part of the frame and projecting horizontally therefrom, an upper jaw slidably mounted on the frame for vertical sliding movement and projecting horizontally from the frame in vertical alignment with the lower jaw to clamp a carton between them, means to move the upper jaw vertically on the frame, a vacuum cup, means mounting the vacuum cup on the upper jaw vertically between the upper and lower jaws for horizontal movement outward from the frame to engage a carton and toward the frame for movement of the carton between the jaws, and a vertical lost motion connection between the upper jaw and the vacuum cup whereby the vacuum cup will be raised relative to the lower jaw when the upper jaw is raised to raise the bottom of a carton held by the vacuum cup above the lower jaw and the upper jaw can be lowered into engagement with the top of a carton without lowering the vacuum cup relative to the carton.

2. A carton clamp for use with a lift truck comprising an upright frame, a lower jaw secured rigidly to and projecting horizontally from the lower part of the frame, a head vertically slidable on the frame, power means to move the head vertically on the frame, an upper jaw carried by the head, a vacuum cup, and means mounting the vacuum cup on the head vertically between the upper and lower jaws for horizontal movement outward from the frame to engage a carton and toward the frame for movement of the carton between the jaws, the mounting means including a vertically slidable lost motion connection whereby the head can move downward to move the upper jaw into engagement with the top of a carton without moving the vacuum cup downward.

3. The carton clamp of claim 2 including power means connected to the mounting means to move the vacuum cup horizontally.

4. A carton clamp for use with a lift truck comprising an upright frame, a lower jaw secured to and projecting horizontally from the lower part of the frame, a head vertically slidable on the frame, power means to move the head vertically on the frame, an upper jaw carried by the head, the head including a horizontal outwardly extending rail, a carriage slidable on the rail, a vacuum cup, and means supporting the vacuum cup from the carriage vertically between the upper and lower jaws for limited vertical lost motion relative thereto.

5. The carton clamp of claim 4 including power means to move the carriage on the rail.

6. The carton clamp of claim 4 including spring means to urge the carriage outwardly on the rail, and power means to slide the carriage inwardly on the rail against the spring means.

8. A carton clamp for use with a lift truck comprising an upright frame, a lower jaw secured rigidly to and projecting horizontaily from the lower part of the frame, a head vertically slidable on the frame, power means to move the head vertically on the frame, an upper jaw carried by the head, an arm pivotally mounted on the head closely adjacent to the frame and slidable relative to its pivotal mounting to provide a vertically slidable lost motion connection, and a Vacuum cup carried by the free end of the arm vertically between the upper and lower jaws,

6 and means to turn the arm about its pivotal mounting to cause the vacuum cup to move outward from the frame to engage a carton and toward the frame to move the carton between the jaws.

References Cited in the le of this patent UNITED STATES PATENTS 2,049,850 Lytle et al. Aug. 4, 1936 2,799,417 Morrell July 16, 1957 2,899,088 Corbin Aug. 1l, 1959 2,942,745 Horton June 28, 1960 2,973,876 Voss Mar. 7, 1961 

1. A CARTON CLAMP FOR USE WITH A LIFT TRUCK COMPRISING AN UPRIGHT FRAME FOR MOUNTING ON A LIFT TRUCK, A LOWER JAW SECURED RIGIDLY TO THE LOWER PART OF THE FRAME AND PROJECTING HORIZONTALLY THEREFROM, AN UPPER JAW SLIDABLY MOUNTED ON THE FRAME FOR VERTICAL SLIDING MOVEMENT AND PROJECTING HORIZONTALLY FROM THE FRAME IN VERTICAL ALIGNMENT WITH THE LOWER JAW TO CLAMP A CARTON BETWEEN THEM, MEANS TO MOVE THE UPPER JAW VERTICALLY ON THE FRAME, A VACUUM CUP, MEANS MOUNTING THE VACUUM CUP ON THE UPPER JAW VERTICALLY BETWEEN THE UPPER AND LOWER JAWS FOR HORIZONTAL MOVEMENT OUTWARD FROM THE FRAME TO ENGAGE A CARTON AND TOWARD THE FRAME FOR MOVEMENT OF THE CARTON BETWEEN THE JAWS, AND A VERTICAL LOST MOTION CONNECTION BETWEEN THE UPPER JAW AND THE VACUUM CUP WHEREBY THE VACUUM CUP WILL BE RAISED RELATIVE TO THE LOWER JAW WHEN THE UPPER JAW IS RAISED TO RAISE THE BOTTOM OF A CARTON HELD BY THE VACUUM CUP ABOVE THE LOWER JAW AND THE UPPER JAW CAN BE LOWERED INTO ENGAGEMENT WITH THE TOP OF A CARTON WITHOUT LOWERING THE VACUUM CUP RELATIVE TO THE CARTON. 